This invention relates to an inference system that executes the inference process, using a knowledge base in which knowledge about various objects is distributed to frames.
In the field of AI (Artificial Intelligence), such as the expert systems, a knowledge representation system is required which can flexibly describe knowledge about certain objects or concepts, and is suitable for accessing, controlling and managing that knowledge easily.
As one of such knowledge representation systems, a frame system is known in which knowledge about various objects is categorized into frames. In the frame knowledge representation system, a frame of an object consists of several sets of slot-value pairs. The slot represents the attribute of that object, e.g., color, weight, "is-a" and "have". The value indicates an attribute value of that object, e.g., white and 50 g, or the names of other objects, e.g. dog. In the frame representation system, knowledge is stored in a way similar to the structure of human knowledge. The frame representation system can describe knowledge in details and in various ways.
In the inference system using a knowledge base which is based on frame system, the attributes of an object are searched by traversing the link of the "is-a" slot, when they do not exist in the frame of the object. In many cases, a frame has "significant attributes "and" not significant attributes" at the same time, and they exist in different links. And some objects are related to each other to different degrees.
However, the conventional inference system using the frame knowledge representation system cannot distinguish the strength of such attributes or relations among different objects. Conventional inference systems frequently fail to access certain simple knowledge that they should be expected to accomplish easily. Also in these systems, unexpected, irrelevant accessing of knowledge prevents the rapid execution of inference processing.